[PATCH] clocksource; armada-370: implement ARM delay timer

[PATCH] clocksource; armada-370: implement ARM delay timer

[Russell King]

Implement an ARM delay timer to be used for udelay() on Armada 37x
platforms.  This allows us to skip the delay loop calibration at boot,
saving 180ms on the boot time of the kernel (which is around 10%).

It also means that udelay() will be unaffected by CPU frequency changes
when cpufreq is enabled on these platforms.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
 arch/arm/Kconfig                         |  1 +
 arch/arm/plat-orion/time.c               | 13 +++++++++++++
 drivers/clocksource/time-armada-370-xp.c | 14 ++++++++++++++
 3 files changed, 28 insertions(+)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index f3dfca632a8a..194569c23271 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -10,6 +10,7 @@ config ARM
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_CMPXCHG_LOCKREF
+	select ARCH_WANT_FRAME_POINTERS
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select BUILDTIME_EXTABLE_SORT if MMU
 	select CLONE_BACKWARDS
diff --git a/arch/arm/plat-orion/time.c b/arch/arm/plat-orion/time.c
index 8085a8aac812..ffb93db68e9c 100644
--- a/arch/arm/plat-orion/time.c
+++ b/arch/arm/plat-orion/time.c
@@ -18,6 +18,7 @@
 #include <linux/irq.h>
 #include <linux/sched_clock.h>
 #include <plat/time.h>
+#include <asm/delay.h>
 
 /*
  * MBus bridge block registers.
@@ -188,6 +189,15 @@ orion_time_set_base(void __iomem *_timer_base)
 	timer_base = _timer_base;
 }
 
+static unsigned long orion_delay_timer_read(void)
+{
+	return ~readl(timer_base + TIMER0_VAL_OFF);
+}
+
+static struct delay_timer orion_delay_timer = {
+	.read_current_timer = orion_delay_timer_read,
+};
+
 void __init
 orion_time_init(void __iomem *_bridge_base, u32 _bridge_timer1_clr_mask,
 		unsigned int irq, unsigned int tclk)
@@ -202,6 +212,9 @@ orion_time_init(void __iomem *_bridge_base, u32 _bridge_timer1_clr_mask,
 
 	ticks_per_jiffy = (tclk + HZ/2) / HZ;
 
+	orion_delay_timer.freq = tclk;
+	register_current_timer_delay(&orion_delay_timer);
+
 	/*
 	 * Set scale and timer for sched_clock.
 	 */
diff --git a/drivers/clocksource/time-armada-370-xp.c b/drivers/clocksource/time-armada-370-xp.c
index 2162796fd504..d93ec3c4f139 100644
--- a/drivers/clocksource/time-armada-370-xp.c
+++ b/drivers/clocksource/time-armada-370-xp.c
@@ -45,6 +45,8 @@
 #include <linux/percpu.h>
 #include <linux/syscore_ops.h>
 
+#include <asm/delay.h>
+
 /*
  * Timer block registers.
  */
@@ -249,6 +251,15 @@ struct syscore_ops armada_370_xp_timer_syscore_ops = {
 	.resume		= armada_370_xp_timer_resume,
 };
 
+static unsigned long armada_370_delay_timer_read(void)
+{
+	return ~readl(timer_base + TIMER0_VAL_OFF);
+}
+
+static struct delay_timer armada_370_delay_timer = {
+	.read_current_timer = armada_370_delay_timer_read,
+};
+
 static void __init armada_370_xp_timer_common_init(struct device_node *np)
 {
 	u32 clr = 0, set = 0;
@@ -287,6 +298,9 @@ static void __init armada_370_xp_timer_common_init(struct device_node *np)
 		TIMER0_RELOAD_EN | enable_mask,
 		TIMER0_RELOAD_EN | enable_mask);
 
+	armada_370_delay_timer.freq = timer_clk;
+	register_current_timer_delay(&armada_370_delay_timer);
+
 	/*
 	 * Set scale and timer for sched_clock.
 	 */
-- 
2.1.0

[PATCH] clocksource; armada-370: implement ARM delay timer

[Andrew Lunn]

On Mon, Oct 19, 2015 at 04:03:31PM +0100, Russell King wrote:
> Implement an ARM delay timer to be used for udelay() on Armada 37x
> platforms.  This allows us to skip the delay loop calibration at boot,
> saving 180ms on the boot time of the kernel (which is around 10%).
> 
> It also means that udelay() will be unaffected by CPU frequency changes
> when cpufreq is enabled on these platforms.
> 
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
> ---
>  arch/arm/Kconfig                         |  1 +
>  arch/arm/plat-orion/time.c               | 13 +++++++++++++
>  drivers/clocksource/time-armada-370-xp.c | 14 ++++++++++++++
>  3 files changed, 28 insertions(+)
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index f3dfca632a8a..194569c23271 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -10,6 +10,7 @@ config ARM
>  	select ARCH_SUPPORTS_ATOMIC_RMW
>  	select ARCH_USE_BUILTIN_BSWAP
>  	select ARCH_USE_CMPXCHG_LOCKREF
> +	select ARCH_WANT_FRAME_POINTERS
>  	select ARCH_WANT_IPC_PARSE_VERSION
>  	select BUILDTIME_EXTABLE_SORT if MMU
>  	select CLONE_BACKWARDS

Hi Russell

Does this hunk belong in the patch?

Thanks
	Andrew

[PATCH] clocksource; armada-370: implement ARM delay timer

[Russell King - ARM Linux]

On Mon, Oct 19, 2015 at 05:15:50PM +0200, Andrew Lunn wrote:
> On Mon, Oct 19, 2015 at 04:03:31PM +0100, Russell King wrote:
> > Implement an ARM delay timer to be used for udelay() on Armada 37x
> > platforms.  This allows us to skip the delay loop calibration at boot,
> > saving 180ms on the boot time of the kernel (which is around 10%).
> > 
> > It also means that udelay() will be unaffected by CPU frequency changes
> > when cpufreq is enabled on these platforms.
> > 
> > Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
> > ---
> >  arch/arm/Kconfig                         |  1 +
> >  arch/arm/plat-orion/time.c               | 13 +++++++++++++
> >  drivers/clocksource/time-armada-370-xp.c | 14 ++++++++++++++
> >  3 files changed, 28 insertions(+)
> > 
> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > index f3dfca632a8a..194569c23271 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -10,6 +10,7 @@ config ARM
> >  	select ARCH_SUPPORTS_ATOMIC_RMW
> >  	select ARCH_USE_BUILTIN_BSWAP
> >  	select ARCH_USE_CMPXCHG_LOCKREF
> > +	select ARCH_WANT_FRAME_POINTERS
> >  	select ARCH_WANT_IPC_PARSE_VERSION
> >  	select BUILDTIME_EXTABLE_SORT if MMU
> >  	select CLONE_BACKWARDS
> 
> Hi Russell
> 
> Does this hunk belong in the patch?

Bah.  Neither does the other change to arch/arm/mach-mvebu/time.c !
Slip up using git commit -a after _manually_ adding just the clocksource
file.

-- 
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

[PATCH] clocksource; armada-370: implement ARM delay timer

[Gregory CLEMENT]

Hi Russell,
 
 On lun., oct. 19 2015, Russell King <rmk+kernel@arm.linux.org.uk> wrote:

> Implement an ARM delay timer to be used for udelay() on Armada 37x
> platforms.  This allows us to skip the delay loop calibration at boot,
> saving 180ms on the boot time of the kernel (which is around 10%).
>
> It also means that udelay() will be unaffected by CPU frequency changes
> when cpufreq is enabled on these platforms.
>
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
> ---
>  arch/arm/Kconfig                         |  1 +
>  arch/arm/plat-orion/time.c               | 13 +++++++++++++

You spoke only about the armada37x but you also modified the timer of
the orion platforms.

Could you split your patch in two part?

Then the arch/arm/plat-orion/time.c related part would be applied
through the mvebu tree and the drivers/clocksource/time-armada-370-xp.c
through the clocksource tree.


>  drivers/clocksource/time-armada-370-xp.c | 14 ++++++++++++++
>  3 files changed, 28 insertions(+)
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index f3dfca632a8a..194569c23271 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -10,6 +10,7 @@ config ARM
>  	select ARCH_SUPPORTS_ATOMIC_RMW
>  	select ARCH_USE_BUILTIN_BSWAP
>  	select ARCH_USE_CMPXCHG_LOCKREF
> +	select ARCH_WANT_FRAME_POINTERS

Is it related to this patch?

Thanks,

Gregory
>  	select ARCH_WANT_IPC_PARSE_VERSION
>  	select BUILDTIME_EXTABLE_SORT if MMU
>  	select CLONE_BACKWARDS

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com